James Ward kept Great Britain's hopes to qualifying for next year's Davis Cup World Group alive after defeating Dmitry Tursunov in a five-set thriller in Coventry.
Despite taking the opening set, Tursunov had Russia on the brink of taking an unassailable lead after going two sets to one ahead having saved four break points in the second and recovered from behind in the third.
But Ward, ranked 214 in the world, fed off a raucous home crowd and capitalised on Tursunov's frustration with the line judges, to square the match at two sets all.
And with the contest in its' fourth hour, Ward completed a remarkable turnaround to shock the former top 20 player and win 6-2 5-7 5-7 6-4 6-4 to send the tie into a deciding rubber between Dan Evans and Evgeny Donskoy.
Jonny Marray and Colin Fleming's doubles win on Saturday meant Britain remained in the hunt to qualify for the Davis Cup World Group play-offs but required victories in both of the day three singles to turn around a 2-1 deficit.
Ward had suffered the ignominy of defeat after leading by two sets and a break in the tie's second rubber on Friday against Donskoy, and faced Russia's highest ranked player in Tursunov, who had gone the distance against Evans in the opening match.
Keen to ride on the momentum created by Marray and Fleming's lightning doubles win, Ward began in similarly clinical fashion, losing just three points in his opening three service games.
That lay down the foundations for Ward to attack the brittle Tursunov service game, reaching deuce as the Russian's running forehand beat the baseline, before the world No.67 edged ahead 4-3.
Further joy was to come in the next Tursunov service game, following a comfortable Ward hold; a break came the Briton's way after successive wayward backhands from the ex-top 20 player.
And Ward served out the set to love, having dropped just three points on his serve to hand Britain the best possible start in the opening rubber of the day.
Things could have got even better in the first game of the second set, but successive erratic backhands saw Tursunov recover from break point down.
Another consummate hold allowed Ward onto the front foot again on the Tursunov serve, a ferocious forehand winner giving an indication to his intensions as he prayed on his opponents' a weak drop shot for 0-30.
The next game it was Ward's turn to recover from 0-30, which he did with undue ease and after serving out to love in his next service game he exerted more pressure on Tursunov, but an ace salvaged a second break point of the set.
Both players held to love and Ward had to be at his best to prevent Tursunov taking the opening set at 5-4, when 15-30 down but his unfaultable serve hauled him out of trouble.
And that resilience almost paid dividends as a punishing forehand winner following a mid-court return from Tursunov, set up two break points but his 30 year old opponent produced two stinging first serves.
It was the break that Tursunov required to grab the initiative, taking the second set 7-5 from his very first break point of the match, as Ward's cross-court forehand crashed into the net.
The 26 year old Brit's inability to stamp his mark on the match was evident in the early stages of the third set, as Ward broke in the opening game, only for Tursunov to take the second of two break point chances to square the set.
And by the sixth game Tursunov had turned the set on its head as Ward went long with a running forehand at 15-40, an advantage cemented as Russia took a 5-2 lead.
Ward did stem the flow and then with Tursunov serving for a two sets to one lead, found a brilliant cross court forehand to convert the second of two break point chances to hand Britain a much needed lifeline.
That salvation was nearly short lived as two stunning Tursunov returns forged a set point, only for Ward to keep his nerve and level at 5-5.
The former AGEON international champion was unperturbed, holding to love and then ruining all Ward's good work by taking the last of three break points to snatch the third set and leave Russia on the brink of qualification for the World Group Play Offs.
Two successive double faults gave Ward a fortuitous 3-1 lead at the start of the fourth set, as Tursunov's calm demeanour began to show signs of breaking; being handed a court violation for swearing at the crowd before further discussion with the chair umpire.
The distraction allowed Ward to serve out the fourth set without alarm as Britain were handed hope of taking the tie to a decisive fifth match.
At 2-2, a scintillating exchange saw Tursunov blink first and then throw in an untimely double fault to give Ward the crucial break.
The London-born player recovered from 0-30, amid swathes of quality groundstroke's from Tursunov, a cracking backhand cross-court taking him to within a game of victory, and duly served out the match to take the final set and set up a grand-stand finale.